/*
 * Copyright (c) 2006
 * Francois Dumont
 *
 * This material is provided "as is", with absolutely no warranty expressed
 * or implied. Any use is at your own risk.
 *
 * Permission to use or copy this software for any purpose is hereby granted
 * without fee, provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is granted,
 * provided the above notices are retained, and a notice that the code was
 * modified is included with the above copyright notice.
 *
 */

#ifndef CPPUNIT_TIMER_H
#define CPPUNIT_TIMER_H

#if defined (_WIN32)
#  define CPPUNIT_WIN32_TIMER
#  include <windows.h>
#endif

class Timer
{
public:
	Timer()
	{
#if defined (CPPUNIT_WIN32_TIMER)
		m_start.LowPart = m_restart.LowPart = m_stop.LowPart = 0;
		m_start.HighPart = m_restart.HighPart = m_stop.HighPart = 0;
		QueryPerformanceFrequency(&m_frequency);
#endif
	}

	void start()
	{
#if defined (CPPUNIT_WIN32_TIMER)
		QueryPerformanceCounter(&m_start);
#endif
	}

	void restart()
	{
#if defined (CPPUNIT_WIN32_TIMER)
		QueryPerformanceCounter(&m_restart);
		if (m_start.HighPart == 0 && m_start.LowPart == 0)
		{
			m_start = m_restart;
		}
#endif
	}

	void stop()
	{
#if defined (CPPUNIT_WIN32_TIMER)
		LARGE_INTEGER stop;
		QueryPerformanceCounter(&stop);
		if ((m_stop.HighPart != 0 || m_stop.LowPart != 0) &&
		        m_restart.HighPart != 0 && m_restart.LowPart != 0)
		{
			m_stop.HighPart += (stop.HighPart - m_restart.HighPart);
			if (stop.LowPart < m_restart.LowPart)
			{
				if (m_restart.LowPart - stop.LowPart > m_stop.LowPart)
				{
					m_stop.HighPart -= 1;
				}
				m_stop.LowPart -= m_restart.LowPart - stop.LowPart;
			}
			else
			{
				if (stop.LowPart - m_restart.LowPart > 0xFFFFFFFF - m_stop.LowPart)
				{
					m_stop.HighPart += 1;
				}
				m_stop.LowPart += stop.LowPart - m_restart.LowPart;
			}
		}
		else
		{
			m_stop = stop;
		}
#endif
	}

	double elapsedMilliseconds() const
	{
#if defined (CPPUNIT_WIN32_TIMER)
		LARGE_INTEGER elapsed;
		elapsed.HighPart = m_stop.HighPart - m_start.HighPart;
		elapsed.LowPart = m_stop.LowPart - m_start.LowPart;
		return (double)elapsed.QuadPart / (double)m_frequency.QuadPart * 1000;
#else
		return 0;
#endif
	}

	static bool supported()
	{
#if defined (CPPUNIT_WIN32_TIMER)
		return true;
#else
		return false;
#endif
	}

private:
#if defined (CPPUNIT_WIN32_TIMER)
	LARGE_INTEGER m_frequency;
	LARGE_INTEGER m_start, m_stop, m_restart;
#endif
};

#endif
